1. Field of the Invention
This invention relates to sampling devices for automatically obtaining samples of gastric and intestinal fluids in the digestive tracts of humans and animals and for use in determining the presence of free hydrochloric acid and lactic acid in the gastric fluids.
2. Description of the Prior Art
Examination of the contents of the different parts of the gastrointestinal tract plays a great role in diagnostic and medical research. Information from these examinations can be of great importance for diagnosing diseases of stomach, duodenum, gallbladder and pancreas, as well as for diagnosing certain blood diseases.
The determination of the presence or absence of free hydrochloric acid and lactic acid in the digestive tract is especially important and useful. The absence of free hydrochloric acid in the gastric fluid is a characteristic finding of pernicious anemia. The absence of hydrochloric acid together with the presence of lactic acid in the gastric fluid indicates for advanced carcinoma of the stomach.
Stomach tubes are the normal instruments for collecting samples of the contents of the stomach and duodeum. As is known, these are long, flexible tubes which are inserted to the digestive tract through the patient's mouth or nose, and then fluid from the actual part of the digestive tract is aspirated through the tube. The examination normally takes place under X-ray control, to check for proper positioning of the end of the tube in the digestive tract.
Intubation of the digestive tract using these methods is difficult, and for patient a very unpleasant intervention. It is a burden for the patient, both physically and psychologically, and it is often impossible to examine patients who are especially sensitive, physically weak or who have heart disease.
The stress to which the patient is subjected during intubation of the stomach or duodenum can have a disturbing influence on the function of the digestive organs, and consequently, in some instances the test results may be inconclusive or erroneous.
Intubation of the digestive tract is an expensive examination. It is a very time-consuming examination for the doctor, and demands the help of highly qualified nurses, a suitable place with comfortable beds where the patients can be examined, and access to X-ray apparatus. The examination immobilizes the patient for several hours, and exposes him to the risks of X-ray exposure.
The above mentioned difficulties and hazards associated with the collection of intestinal fluid preclude the use of conventional technique for mass-examinations, which are especially important to reveal cases of gastric cancer.
In recent years an application of swallowable capsules for the purpose of collecting samples of gastric fluids has been suggested. Examples of such devices are described in U.S. Pat. No. 3,118,439 issued to J. Perrenond on Jan. 21, 1964 and in U.S. Pat. No. 3,485,235 issued to R. Felson on Dec. 23, 1969. In using these patented devices, the opening of the swallowed capsule in the alimenttary canal and the intake of the sample of fluid is externally controlled by placing the patient in the high-frequency electromagnetic field. This examination however requires highly skilled medical personnel, the use of an X-ray device, to observe the passage of the capsule through the alimentary canal, and this procedure itself is likely to induce psychological stress in the patient.